You may just keep pitch shifting (transpose) one of the two until you get them in the same key. Depending on where you got the samples from, say from a turntable with the pitch adjustment faster or slower or a wornout tape player, you may be in between notes and transposing by whole tones (F-G) or semitones (F-F sharp) will still have you out of tune. So, you would have to transpose the pitch by cents (100 increments in 1 semitone) which is tedious work. I would resample without any pitch adjustment first if possible. Although you may just have samples in two different keys that do not work together even if they have notes in the same scale. Hard to say without hearing it. I would just playing with it, definitely a good learning experience, been there plenty of times